1. Field of the Invention
This invention relates in general to railway tank cars and particularly to tank cars which are connected by manifolds so as to allow them to be loaded or unloaded from a single car of the interconnected cars without moving the train so that the cars can be consecutively loaded and unloaded.
2. Description of the Prior Art
A number of patents have issued on systems and apparatus for loading a string of tank cars from a single location wherein the cars are loaded from manifolds extending between them so that the entire series of cars can be loaded. For example, U.S. Pat. No. 3,897,807 entitled "Manifoled Tank Cars For Unit Train Service" discloses such system and explains the requirements for providing a free vapor space or "outage" above the liquid lading at the top of the tanks and furthermore describes the desirability of maintaining the flexible connecting conduits between adjacent tank cars empty of lading. The description of this patent relating to this problem is hereby incorporated by reference. Other patents which describe various apparatus for interconnecting tank cars for unit train service are U.S. Pat. Nos. 4,079,760, 4,002,192, 4,304,271, 4,008,739 and 4,007,766. The disclosure in these patents is hereby incorporated by reference.